A tephrochronology for the Lateglacial palynological record of the Endinger Bruch (Vorpommern,north‐east Germany)     

C. S. Lane  P. De Klerk  V. L. Cullen 《第四纪科学杂志》2012,27(2):141-149

The tephrostratigraphy of lake sediments in the Endinger Bruch provides the first robust age model for the Lateglacial palynological records of Vorpommern (north‐east Germany). Cryptotephra investigations revealed six tephra layers within sediments spanning from Open vegetation phase I (～Bølling, ～15 ka) to the Early Holocene Betula/Pinus forest phase (～Pre‐boreal, ～10.5 ka). Four of these layers have been correlated with previously described tephra layers found in sites across Europe. The Laacher See Tephra (Eifel Volcanic Field) is present in very high concentrations within sediments of the Lateglacial Betula (/Pinus) forest phase (～Allerød). The Vedde Ash (Iceland) lies midway through Open vegetation phase III (～Younger Dryas). The Hässeldalen and the Askja tephras (Iceland) lie in the Early Holocene Betula/Pinus forest phase (～Preboreal). These tephra layers have independently derived age estimates, which have been imported into the Endinger Bruch record. Furthermore, the layers facilitate direct correlation of the regional vegetation record with other palaeoenvironmental archives, which contain one or more of the same tephra layers, from Greenland to Southern Europe. In doing this, localized variations are confirmed in some aspects of the pollen stratigraphy; however, transitions between the main vegetation phases appear to occur synchronously (within centennial errors) with the equivalent environmental transitions observed in sites across the European continent. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Vegetation sensitivity to climate changes and human impact in the Harghita Mountains (Eastern Romanian Carpathians) over the past 15 000 years          下载免费PDF全文

IOAN TANŢĂU  ANGELICA FEURDEAN  JACQUES‐LOUIS DE BEAULIEU  MAURICE REILLE  SORINA FĂRCAŞ 《第四纪科学杂志》2014,29(2):141-152

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A record of Lateglacial and early Holocene environmental and ecological change from southwestern Connecticut,USA     

W. Wyatt Oswald  David R. Foster  Elaine D. Doughty  Edward K. Faison 《第四纪科学杂志》2009,24(6):553-556

Analyses of a sediment core from Highstead Swamp in southwestern Connecticut, USA, reveal Lateglacial and early Holocene ecological and hydrological changes. Lateglacial pollen assemblages are dominated by Picea and Pinus subg. Pinus, and the onset of the Younger Dryas (YD) cold interval is evidenced by higher abundance of Abies and Alnus viridis subsp. crispa. As climate warmed at the end of the YD, Picea and Abies declined and Pinus strobus became the dominant upland tree species. A shift from lacustrine sediment to organic peat at the YD–Holocene boundary suggests that the lake that existed in the basin during the Lateglacial interval developed into a swamp in response to reduced effective moisture. A change in wetland vegetation from Myrica gale to Alnus incana subsp. rugosa and Sphagnum is consistent with this interpretation of environmental changes at the beginning of the Holocene. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

乔治王岛菲尔德斯半岛周围海岸地貌研究          下载免费PDF全文

刘耕年  崔之久 《极地研究》1990,2(3):18-26

本文对南设得兰群岛乔治王岛菲尔德斯半岛周围现代和上升海岸地貌进行了研究。认为现代海岸地貌有三类:碎屑海岸、基岩海岸和冰崖海岸。对碎屑海岸受负载浮冰的波浪作用造成的各种现象进行了成因和类型研究。系统研究上升海岸之后得出结论,该区上升海岸地貌以海拔20米为界,上下分别属较老组和较新组。海岸平均上升速度为10毫米/年。  相似文献   

First record of an odontaspidid shark in New Zealand waters     

J. A. F. Garrick 《新西兰海洋与淡水研究杂志》2013,47(4):621-630

Photographs and a preserved head are identified as Odontaspis herbsti Whitley, 1950, an Australian sand shark growing to about 3 m long and similar to the Mediterranean O. ferox Risso, but differing in having a uniform grey body without black markings on the back or sides. No living odontaspidids have previously been reported from New Zealand. Six specimens were trawled in 119–165 m off Table Cape, Hawke Bay, in October‐November 1972. Californian and. East Atlantic (Madeira) specimens are treated as conspecific with O. herbsti. It is suggested that O. herbsti is normally an inhabitant of the continental slope, and that the present records are of a few individuals that have strayed on to the shelf.  相似文献   

Late Quaternary vegetation and fire history in the northernmost Nothofagus forest region: Mallín Vaca Lauquen,Neuquén Province,Argentina     

Vera Markgraf  Cathy Whitlock  R. Scott Anderson  Adriana García 《第四纪科学杂志》2009,24(3):248-258

The last 16 000 cal. a of vegetation, fire and limnological history are described from the steppe‐forest ecotone in the northernmost Nothofagus forest region east of the Andes (Mallín Vaca Lauquen, Neuquén Province, Argentina, latitude 36° 51.336′ S, longitude 71° 02.538′ W). Between 16 000 and 14 800 cal. a BP, scrub steppe with substantial open ground expanded in formerly glaciated valleys, whereas Nothofagus–Prumnopitys andina woodland covered mountain slopes. The site was a relatively deep and unproductive small lake at this time. After 14 800 cal. a BP, both steppe and woodland vegetation became denser, indicating increased moisture and temperatures, although not to present levels. The lake was still relatively deep and dystrophic, but became more alkaline by 10 000 cal. a BP. Between 8900 and 5500 cal. a BP, conditions were markedly drier than before; a Cyperaceae marsh developed and disturbance taxa increased. After 5500 cal. a BP, moisture increased but varied greatly, as evidenced by fluctuating water levels and high fire activity from 5500 to 4400 cal. a BP and from 2300 to 1000 cal. a BP. Human activity, in terms of forest clearance and livestock grazing, is documented in the uppermost levels. The evidence of high environmental variability in the middle and late Holocene is consistent with the onset or strengthening of the El Niño–Southern Oscillation, but differences in the timing of fire activity among sites on the west and east sides of the Andes suggest that fuel conditions were important in determining the local occurrence of fire. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

A high-resolution record of Lateglacial and early Holocene marine sediments from southwestern Sweden; with special emphasis on environmental changes close to the Pleistocene-Holocene transition and the influence of fresh water from the Baltic basin     

Helene Bergsten 《第四纪科学杂志》1994,9(1):1-12

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某电厂煤码头煤尘对海洋环境影响的估算     

张观希  杜完成  温伟英 《热带海洋学报》1995,(4)

以广东某电厂煤码头为例，探讨临海煤码头落海煤尘对海洋环境的影响。文中阐述了点源和面源起尘量的估算。根据风速、煤粒下降速度、落差高度等计算煤码头扬尘入海量。依据煤尘煤粒到达海区的量计算煤尘入海引起海水悬浮物的增量等。文中还讨论了落海煤尘煤粒对海洋环境水质、沉积物和海洋生物的影响，认为其主要是对海水水质悬浮物、海洋生物光合作用以及沉积物有机质、硫化物含量的影响等。  相似文献   

Relict Shorelines and Ice Flow Patterns of the Northern Puget Lowland From Lidar Data and Digital Terrain Modelling   总被引：1，自引：0，他引：1  

Dori J. Kovanen  Olav Slaymaker 《Geografiska Annaler: Series A, Physical Geography》2004,86(4):385-400

Airborne lidar data from the northern Puget Lowland provide information on the spatial variability and amplitude of raised postglacial shorelines, marine deltaic features and glaciomarine sediments deposited between approximately c. 12 920 and 11 050 ¹⁴C yr BP (15 960‐12 364 cal yr BP). Relict shorelines preserved in embayments on Whidbey and Camano islands (between 47°54′N and 48°24′N) are found up to an altitude of c. 90 m and record glacio‐isostatic movements attributed to postglacial rebound. The tilt of the regional minimum highstand sea level surface to the north of 0.80 m km^?1, with local variability from 0.25 m km^?1 to 0.77 m km^?1, is consistent with previous studies (Thorson 1989; Dethier et al. 1995). The local variability is related to the uncertainty in the depth of the water column above these features at the time of deposition and probable tectonic deformation. The information generated by these lidar data is most valuable in posing new research questions, generating alternative research hypotheses to those already formulated in the northern Puget Lowland.  相似文献   

多年冻土区采暖房屋架空不通风式桩基础应用   总被引：1，自引：0，他引：1  

李英武  马伟芳 《冰川冻土》1989,11(2):167-171

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